Over 100,000 Unlikely Spider Species in a Cave Built the Largest Web in the World

Spiders tend to be solitary creatures, so imagine researchers’ surprise when they discovered more than 100,000 arachnids sharing what is believed to be the largest web ever recorded.

The website measures a breathtaking 1,140 square feet (106 square meters) and is located in the Sulfur Cave on the border between Albania and Greece. According to scientists writing in the journal Underground biology, This is the first reported incident of cave spiders building webs together.

After further investigation, the team determined the composition of the colony. According to their estimates, it would be composed of 69,000 Domestic tegenaria (also known as the barn funnel weaver or house spider) and more than 42,000 Prinerigone vagans (a type of leaf weaver).

Learn more: Spiders will hunt in groups and share meals if they have enlarged brain structures

The largest spider web in the Sulfur Cave

The web was first discovered in 2022 by cavers from the Czech Speleological Society. It exists in a permanently dark area in a narrow passage about 50 meters from the cave entrance.

As its name suggests, Sulfur Cave contains high concentrations of sulfurous gas. This is due to a sulfur current that flows from the depths of the cave to its entrance. The result is an extremely harsh living environment that nevertheless supports an entire ecosystem of adapted creatures. In the study, researchers noted the presence of worms, beetles, scorpions, “sometimes fish” and, of course, spiders.

Spiders are unlikely roommates

Through DNA analysis, the team discovered that Domestic T. And P. vagans were the two dominant species. While Domestic T. was responsible for weaving the canvas, the smallest P. vagans assumed the role of squatter. This was surprising because neither species is known for community living or gregarious behavior, according to the study. Domestic T. is a cosmopolitan spider, often found living in buildings and near human settlements, while the British Arachnological Society states P. vagans inhabit moist environments, such as grassy meadows and salt marshes.

Perhaps what makes these eight-legged roommates’ living situation even stranger is the fact that Domestic T. one would expect him to tackle P. vagans. Researchers suggest that it may be the cave itself, particularly the lack of light, that allows these two species to coexist peacefully.

Simply put, more aggressive is Domestic T. cannot see their neighbors and may not even know they are there. Instead of turning on each other, the researchers suspect that the spiders feed on a diet of non-biting midges that live on microbial biofilms produced by sulfur-oxidizing bacteria.

Additional analysis revealed that high dietary sulfur intake impacted the spiders’ microbiome, decreasing gut bacterial diversity compared to spiders of the same species living outside the cave.

Counting Sulfer Cave Spiders

Upon inspection, the researchers discovered that the web was essentially a patchwork of thousands of individual funnel-shaped webs connected together. The team then calculated the density of Domestic T. living in the colony by counting the number of funnel webs in 30 6 x 6 inch (15 x 15 centimeter) quadrants and applying these calculations to the entire structure.

The density of P. vagans was estimated by counting individuals in 6 x 4 inch (15 x 10 centimeter) quadrants.

The researchers warned: “The methodology used to estimate spider density may lead to overestimation due to the presence of discarded funnel webs that are difficult to distinguish from used ones. »

Although this is an overestimate, Sulfur Cave may be a cave to avoid for arachnophobes.

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